L5 Digital Visual Effects - Report

Above is the final result of the Digital Visual Effects project. We recreated a scene from the Gareth Edwards film, Monsters. In the scene, a monster picks up a car and tosses it aside. The reason we chose this sequence is because we wanted to attempt to make a visual effect sequence at night, as it is host to numerous challenges. One of the main challenges found was in the lighting on the 3D model and matching as close as possible to the real world car which it was to replace in the scene. The real world car had reflections which we were not able to recreate in the 3D model, something we have said that if we were able to shoot again, the cars would be parked further apart. We weren't able to shoot again because the car we needed was unavailable, as it was one of Phil Baggot's friend's cars and they were not available after the initial shoot. Colour matching the vehicle at night also proved difficult, which ties in with the light matching. This made it a lot harder to have the 3D car blend seamlessly with the real car for the shot, as it was in one single shot, like how Edwards had done his. Using a focus pull onto the driver of the camera car, the car in front blurs out. The second before the car is lifted, the 3D model is placed into the scene, then the focus shifts back to it. Having watched the scene so many times, we were able to find the exact moment the car was switched. This was crucial. We even noticed that the 3D model only has a vague resemblance to the real one.

IN THE BEGINNING OF THE PROJECT:
When we formed our group, Shaun, Phil and I decided we would go and choose a few different sequences we would like to recreate and look at how they were made. We would then look at them all and see which we thought would be the best and most interesting to try. We opted for Gareth Edwards' monster film, Monsters. What really attracted us to this film was the way Gareth had made the film. It was done with very few people and he edited and composited the film himself with Adobe After Effects, a program we have access to, so we could get a very authentic edit of the film. Also, the monster rig he used was a modified Spider CAT rig in 3Ds Max. He simulated the tentacles with Reactor, however. This meant we could not use a modern version of 3Ds Max.

We worked out a work flow for what we would be making;
Offline editing
Taking BMD flat Log convert to Prores/DNxHD
Linear workflow
Mulitpass compositing including Zdepth
CGI will be rendered in OpenEXR
Planar Tracking

And we took a look at what problems we may run into:
Noise, Rolling Shutter, Difficult shot and the shooting style.
Noise:
The noise is able to throw off the tracking of shots. Noise is especially prevalent in dark shots, which is what our sequence is. If we raise the ISO to give ourselves a brighter shot, we are going to open ourselves up to more noise, so we have to be very careful and shoot on a lower ISO. Noise is always going to be there, but we can remove that in post. At the end of the sequence, however, we will add noise. This will keep the CG elements looking like they belong in the scene.
Rolling Shutter:
Unless the camera has Global Shutter, you will be dealing with this. The sensor scans from top to bottom, meaning that if the camera is moving side to side, your image is going to be skewed, like this: \
For our shot, however, we don't have to worry so much about this, as the majority of the shot will be steadied.
Shooting Style:
We will be avoiding the Shaky Cam/Handheld feel by having the camera stabilised. This would remove the time needed to correct the footage later.
Difficult Shot:
Shooting at night is not ideal. With issues from Noise and high ISOs, to needed good lighting to just see ANYTHING. But what was going to be a real problem was that there are no tutorials to help us with this effect. We have to watch the sequence frame by frame to see when things change, how things change, why he changes it there.

We split the project into sections and worked out who would be working on what parts.

I was tasked with creating the Monster rig - having it ready to attach the tentacles that Shaun was going to make, animating it for the pickup, and animating the car being picked up. Phil would handle the car being thrown aside. I would also have a look at simulations for fog. My skills with Maya were not up to scratch, however and I was unable to make a suitable fog effect.

We also looked at locations.

A good spot for the night shot was this area of Ash Road. It is near where Phil lives and he said that at night, the spot would be perfect, as the street lights are far enough away to not be a problem and the trees blocked the lights from the main road behind. Sadly, shortly after choosing this spot, the council had cut the trees down.

Near me, we found this little area. There were no lights, far enough away from the Ringroad... It seemed perfect!

But the area is fenced off, so we couldn't get cars there.

Shaun suggested Danby Forrest. The problem here is that it's in the middle of nowhere and getting to it would be a pain.

Another possible location I found was Roundhay Park. There are plenty of trees in the area and reasonable access to them by road. 

In the end, we opted for none of these and found a spot on Headingley Campus, which leads towards the student halls. There are a lot of trees and no street lights.

CREATING THE MONSTER:

Gareth Edwards made his monster's rig using 3Ds Max's CAT system. To be true to the film, we decided that's what we would do, too.

Loading up a SPIDER CAT rig and deleting the pedipalps and some of the legs, then adding to them with extra bones was how I would end up making the beast. Aligning the legs into roughly how the monster should have it's legs was a tricky feat. If they weren't right, the movement would be too lopsided or rigid. Getting the right number of bones in the legs would give you the right bend in the legs for when the monster stoops down to pick up the car, then stand back up. Too many bones and it would stoop too low, too few bones and it would look like it was moving on stilts, not being able to bend right and making for awkward movements. It was trial and error to get the rig right. But with how Shaun had got the tentacles simulated and skinned, it was worth the effort.

The standard 3 bone legs did not give a good enough arc in the movement, something which would severely affect the animation. 

I did find, however, that 5 bones would make for a nice arcing movement.

To animate the car being lifted, I would require Shaun's tentacles to be added to the rig, and Phil to have modelled the car. Once these were done, I would match the movement of the car to the movement of the tentacles. The car lift and the tentacles would be rendered separately, as the version that the car was modelled and textured in would not carry across to the previous version which the car was made in. This was a part of our workflow which we had taken into account and were ready for.

Once the car was rendered out in passes, it was ready to be added into the scene along with the tentacles.

SIMULATION:

These were left out, as I was not able to get the fog to react properly. The result was just like thin smoke coming from an emitter. I tried to keyframe the fuel rate in Maya to change the rate that the fog was being created, but in the end, we had to accept defeat. This also was a problem for the dirt hits when the car hits the ground after being picked up by the monster. In the end, we had to resort to a Dirt Charge from Action Essentials. Action Essentials was only to be a last ditch effort, as we wanted to create our elements, ourselves.

When I tried to make the fog and dirt charges, I was using a simulation I had used for another project as a reference as to how to make it.

Explosion Simulation that I made in Maya for the Animation and Simulation module.

I had been able to change the rate the fuel was used, which would stop emitting smoke after a certain amount of time. I could not recreate this with the fog, however.

EDITING:

Shaun, Phil and I each took turns in editing sections of the video. I mainly roto'd out sections to allow the tentacles to pass behind the driver and passenger. I would remove the hard edge of the mask by feathering the edge. This would blend the clips together in a more realistic fashion, allowing the features to effectively bleed into eachother, giving you a slight overlap in colours, assisting in blurring the images. Part of the car landing shot I masked, too. The car rolling into shot would roll in front of the wing mirror, so I masked over it to keep the car outside. I also added Motion Blur to the car as it was picked up. Motion Blur is needed to make elements look realistic. Everything that moves is blurred. It's just how our eyes see things, so if you don't add the Motion Blur, it will stand out really obviously. The down side to adding Motion Blur is that it ups Render times a lot, especially in our scene, where you had multiple objects being blurred, ie, the tentacles and the car.

We used a Gaussian Blur on the car and tentacles for the pulled focus shots and keyframed it so it would match the focus of the footage. We kept a slight blur on the objects because, like with the motion blur, the eye always has some blur to what it sees. By adding the blur to the CG objects, it allows us to keep them fitting in with the scene.

I also added some film grain to the footage at the end, since we had removed grain from the original footage, we could add grain at the end which would include the CG elements.